SAINT-JOHN, JOHN de (d. 1302), lieutenant of Aquitaine, was the son of Robert de Saint-John and his wife Agnes, daughter of William de Cantelupe. His grandfather, William de Saint-John, was the son of Adam de Port [q. v.], by his marriage with Mabel, the granddaughter and heiress of Roger de Saint-John. In virtue of inheriting Roger's estates, William assumed the name of Saint-John, describing himself as ‘ William de Saint-John, son and heir of Adam de Port.’ The Ports had been an important Hampshire family, having their chief seat at Basing, near Basingstoke, which continued to be the centre of the Saint-John influence.

Robert de Saint-John died in 1267 (Worcester Annals, p. 457), whereupon John received livery of his lands. John also succeeded his father as governor of Porchester Castle. He held land in six counties—Hampshire, Herefordshire, Berkshire, Warwickshire, Kent, and Sussex (cf. Burrows, Brocas Family of Beaurepaire, p. 364). After Basing, his chief centre of power was Halnaker, near Chichester in Sussex, round which he held four manors (cf. Cal. Patent Rolls, 1281–92, p. 67). In November 1276 he was one of the magnates present at the council at which judgment was given against Llywelyn of Wales. In 1277 and in 1282 he took part in Edward I's two great invasions of Wales, and in 1283 was summoned to the Shrewsbury parliament. On 26 April 1286 he received letters of protection for one year on going abroad with the king, and on 16 May nominated Thomas of Basing, clerk, as his attorney in England (ib. pp. 239, 247). His absence, however, was prolonged beyond that period (ib. p. 277), and during Edward I's three years' residence in Aquitaine, between 1286 and 1289, he seems to have been in constant attendance on him. He was busied, for example, in negotiations resulting from Edward's mediation between the kings of Aragon and Naples, and in October 1288 was one of the hostages handed over to Aragon to secure the conditions upon which the prince of Salerno had been released (Fœdera, i. 690). He thus first gained that exceptional experience in Aquitanian affairs that accounts for his subsequent employment in Edward's south French duchy. He was back in England before 2 Feb. 1289 (cf. Cal. Patent Rolls, 1281–92, p. 346). In May 1290 he attended parliament.

On 29 Oct. 1290 Saint-John again received letters of protection for a year, as going abroad on the king's service, but he did not appoint his attorneys until 8 Jan. 1291 (ib. pp. 392, 413). He was now despatched on a mission to Nicholas IV as regards the crusading tenth and the projected crusade (Fœdera, i. 743). In March he was at Tarascon, dealing with business arising out of Edward I's mediation between Sicily and Aragon (ib. i. 744–5). Again, in November, he was once more quitting England for the continent (Cal. Patent Rolls, 1281–92, p. 449). In November 1292 he was in Scotland attending on the king (Hist. Doc. Scotland, i. 371). Various grants followed these services (cf. Cal. Patent Rolls, 1281–92, pp. 465, 483, 511).

In 1293 the relations between Edward I and Philip the Fair became unfriendly, and Saint-John was again despatched to Gascony to act as the king's lieutenant, with two thousand livres tournois as his stipend. His administration of Aquitaine was just and popular (Walter de Hemingburgh, ii. 49). He specially busied himself with strengthening and provisioning the fortified towns and castles, and in providing adequate garrisons for them (Rishanger, Chron. p. 139). Meanwhile, however, Edmund of Lancaster had been tricked into allowing Philip the Fair the temporary possession of the Gascon strongholds. On 3 Feb. 1294 Saint-John received instructions from Edmund to deliver seisin of Gascony to its overlord (Fœdera, i. 793; Champollion Figeac, Lettres des Rois et des Reines d'Angleterre, i. 406–8). He accordingly admitted the French into the castles, sold off the provisions and stores that he had collected, and returned to England by way of Paris (Trivet, p. 330; Rishanger, p. 141; Flores Hist. iii. 271).

Philip treacherously kept possession of Gascony, and Edward I prepared to recover his inheritance by force. Unable to go to Gascony in person, Edward, on 1 July 1294, appointed his nephew John of Brittany as his lieutenant in Aquitaine with Saint-John as seneschal and chief counsellor (Fœdera, i. 85). The expedition finally left Plymouth on 1 Oct. (Hemingburgh, ii. 46–9; cf. Fœdera, i. 808). On 28 Oct. the Gironde was reached. On 31 Oct. Macau was captured. Bourg and Blaye were next subdued, and the fleet sailed up the Garonne to Bordeaux; but, failing to capture so great a town, it went higher up stream to Rions, which was captured, along with Podensac and Villeneuve. Leaving John of Brittany at Rions, Saint-John went, by river and sea, to Bayonne, and attacked the town. On 1 Jan. 1295 the citizens of Bayonne, with whom he was very popular, drove the French garrison into the castle and opened their gates to him. Saint-John sent the ringleaders of the French party to England and attacked the castle, which surrendered eleven days later (Trivet, pp. 334–5; Rishanger, p. 147; Worcester Ann. p. 520). These great successes caused many Gascons to join the English army.

Charles of Valois, the brother of Philip the Fair, now invaded Aquitaine and won back most of Saint-John's conquests in the Garonne valley. Both Saint-John and John of Brittany strove to defend Rions, but became so alarmed at the fall of the neighbouring towns that they abandoned the place, and the French re-entered on 8 April (Guillaume de Nangis, i. 288–9). Much quieter times ensued. In 1296 Edmund of Lancaster took the command, and, after his death, Henry de Lacy, third earl of Lincoln [q. v.] But the brunt of the hard work still fell on Saint-John, who continued to be seneschal. Bayonne remained the centre of the English power, and on 28 Jan. 1297 Saint-John marched with Lincoln to convey provisions to Bellegarde, which was closely besieged by Robert, count of Artois. The army passed through Peyrehorade in safety, and, approaching a wood within three miles of Bellegarde, was divided into two divisions, of which Saint-John led the former. Beyond the wood he was suddenly attacked by the French. Saint-John, though outnumbered, fought bravely; but Lincoln and the second division failed to give him proper support. Night approached, and the Gascon contingent ran away. Supported only by the English knights, Saint-John was utterly defeated, and taken prisoner along with ten other knights (Trivet, pp. 353–4; Rishanger, pp. 168–9; Knighton, i. 363, who calls the place ‘Helregard;’ Langtoft, ii. 280–2; Hemingburgh, ii. 74–6, gives a rather different account, which seeks to explain away the English defeat; (Guillaume de Nangis, i. 295, says that night alone prevented Lincoln's destruction). The prisoners were sent in triumph to Paris, and the French rejoiced over Saint-John's capture as the Philistines rejoiced over that of Samson (Flores Hist. iii. 100). Saint-John was only released after the treaty of L'Aumône in the summer of 1299. His captivity involved him in heavy debts, and on 3 Nov. 1299 he was forced to pledge four of his manors for sixteen years to the merchants of the society of the Buonsignori of Siena (Cal. Patent Rolls, 1292–1301, p. 482).

The Scots war soon furnished Saint-John with new occupation. On 3 Jan. 1300 he was appointed the king's lieutenant and captain in Cumberland, Westmoreland, Lancashire, Annandale, and the other marches west of Roxburgh (ib. p. 484). He was soon busy raising troops and receiving submissions of the Scots favourable to Edward (Hist. Doc. Scotland, ii. 407–8). In the famous siege of Carlaverock in 1300, Saint-John took a conspicuous part, being entrusted with the custody of Edward, the king's son, who was then making his first campaign (Nicolas, Siege of Carlaverock, pp. 42, 46, 50). In 1301 he is described as warden of Galloway and the sheriffdom of Dumfries, as well as of the adjacent marches (Cal. Patent Rolls, 1292–1301, p. 590). In the spring of that year he was appointed, with Earl Warenne and others, to treat at Canterbury of a peace between the English and the Scots with the envoys of Philip the Fair (ib. p. 580). The entries against Saint-John's name in the wardrobe accounts of the twenty-eighth year of Edward I show in detail his losses, confidential charges, and retinue as lieutenant of the western marches (Liber Quotidianus Garderobæ, pp. 176, 183, 200, London, 1787). In January 1301 Saint-John was at the Lincoln parliament, and signed the famous letter of the barons to the pope (Fœdera, i. 926; the description of the signatory as ‘lord of Halnaker’ shows clearly that it was John, and not his son). On 12 July 1302 he was with the king at Westminster (Fœdera, i. 941), but must soon have returned to his border command. He died on Thursday, 6 Sept. 1302, at Lochmaben Castle (‘Ann. London,’ in Stubbs, Chron. Edward I and Edward II, i. 128). He is described as a ‘most faithful and most valiant knight’ (Flores Hist. iii. 387), as ‘discreet, strenuous in arms, and experienced in battles’ (Trivet). ‘No more valiant and prudent man could be found’ (Siege of Carlaverock, p. 46). His arms were argent, on a chief gules, two mullets or, and his crest a lion passant between two palm branches (Siege of Carlaverock, p. 248; Archæological Journal, xxi. 224–6).

Saint-John's wife was Alice, daughter of Reginald FitzPeter, who survived him. Their eldest son, John, was either twenty-eight or thirty years old at his father's death (Calendarium Genealogicum, p. 624), and succeeded to his estates. He had already been for some years actively engaged in war and politics, had fought at Falkirk in 1298 and Carlaverock in 1300 (Gough, Scotland in 1298, p. 152), and had been summoned to parliament in 1299 as ‘John de Saint-John junior.’ The peerage writers take this summons as the beginning of the ‘barony by writ’ (G. E. C., Complete Peerage, i. 256; Nicolas, Historic Peerage, ed. Courthope, p. 412). There is some difficulty in distinguishing father and son in the last years of the former's life, though he is commonly distinguished as ‘John de Saint-John senior.’ The younger John married Isabel, daughter of Hugh Courtenay, and died in 1329. His son and successor, Hugh, died in 1337, and was never summoned to parliament. His heir, Edmund, died in his minority, and the barony fell into abeyance. The estates went to two coheiresses, but ultimately the whole passed to Isabel, Edmund's sister, and to her chil- dren by her second husband, Luke de Poynings. From the Poynings they passed to the Paulets (a pedigree is given on page 365 of Burrows, Brocas Family of Beaurepaire).

Besides the confusion with his son, John de Saint-John, lord of Basing and Halnaker, is often confused with another John de Saint-John of Stanton or Lagham, the son of Roger de Saint-John, an adherent of Simon de Montfort, who was slain at Evesham. These knights represented an Oxfordshire house, whose chief seat was at Stanton Saint-John, four miles east of Oxford, and who also owned the fortified house of Lagham, situated at Godstone in Surrey, of which they possessed half the manor. John de Saint-John ‘of Lagham’ was also summoned to parliament in 1299, and died in 1317, leaving a son and heir, John, aged 40, who died on 8 April 1349, and was the last of his stock summoned to parliament.